please i'm begging for your help with dosage calculations im desperate

8jimi8ICURN · Jul 10, 2009

ive got the conversion factors down perfectly its just setting up and knowing which numbers to put where in the dimensional analysis method.

Calm down! :)

The way to figure out which numbers to put on top, or where to put what is easy. It is given to you in the question:

this are only an example off the top of my head :)

Example- Dr. Ordered 2 grains of Aspirin you have available: Aspirin 60mg/tablet. How many tablets do you give?

Starting unit / 1 x conversion = desired unit / 1

Tablets is the unit that you want to end up with. So write that down at the end of your equation

Starting unit / 1 x conversion x conversion = Tablets / 1

So now what other information do you have to plug in? 2 grains... that is your starting unit

2grains / 1 x conversion x conversion = tablets / 1

So now plug in your conversions and This is where it seems tricky... You just work backwards and arrange your conversions so that it all works out to have your desired unit over 1 at the end of the equation. Conversions are conversions... it doesnt matter which side is on top!

2grains / 1 x 60 mg / 1 grain x 1 tablet / 60 mg = Tablets / 1

So now you go through and cross multiply and cancel out what you can. What you should be left with is

2 /1 x 1 / 1 x 1 tablet / 1= 2 tablets/1 right?

let me know if this helps. If it does i can write up one for you for a drip rate. Just take your time and write down all of your work and don't try to do even the easy ones in your head. If you write down all the information and your formula, you will be able to make sense of it. Good luck! :)

classykaren · Jul 10, 2009

Thank you so much this has stoped me from entering Nursing school , now I think I may be able too. again Thank you so much

Daytonite, BSN, RN · Jul 10, 2009

there are online tutorials listed on post #2 of this sticky thread: https://allnurses.com/general-nursing-student/nursing-math-thread-264395.html - the nursing math thread. please check them out. there are also several links to sites that explain dimensional analysis. whenever i answer a drug calculation question on the student forums i almost always do them by dimensional analysis, also known as the factor label method. you will see my posts responding to these on that same thread above.

some wisdom for you. . .(1) 8th grade level math is all the is required. (2) drug calculations are all word problems; with word problems a picture is always worth a thousand words. the reason most people have trouble with these are because they don't make sense until they get into clinical situations and actually see and hold in their hands the actual things these drug problems are talking about and suddenly light bulbs turn on all over your brains. these problems are based on real life situations that many of you haven't seen yet. if it's possible to go into a nursing lab and actually look at what these drugs look like then these problems make a lot more sense when you read them. (3) there are only 3 terms you need to be interested in: the dose the doctor ordered, the dose you have on hand, and the dose you will be giving. find those and you will get the answer to the question.

BabyLady, BSN, RN · Jul 10, 2009

Some of these word problems contain information that is irrelevant.

You always, always start out with the order...that tells you what units you eventually need to end up with.

For example, if you need drops per minute, and after setting up your problem you'll end up with minute over drops...then you have your problem set up wrong and will get the wrong answer.

Our school, you had to get 95% or better on the exam.

Blondie24 · Jul 12, 2009

Don't stress! I'm currently in Nursing school myself. At my school, we have to get 100% every time we have

a med math calculation test....which is at the start of every semester.

The method I use is: D/H x Q = X

"D" stands for desired amount

"H" stands for available or what is on hand

"Q stands for quantity

"X" stands for what you are solving for

For example:

Ordered Lanoxin 250 mcg IV stat. Supply: ampule labeled 500 mcg/ 2mL. How many mL's will the nurse give?

So, now just plug in the information.

D=250 mcg

H= 500 mcg

Q= 2

X= how many mL's will you administer?

250/500 (2) = x

X= 1 mL

This formula has helped me through lots of med math calculations, with exception to IV drip rates.

Hope this helps!

Valasca · Jul 12, 2009

I have always hated math. For some reason it just never makes any sense to me. I feel your frustration. I cannot do dosage calc using deminsonal analysis....it just doesn't make sense in my brain. I am like you, I never know how to set up the problem. Many people have tried over and over again to teach me dimensional analysis but it never "clicks" in my head. The one way I have found to be really "fool proof" (for me) is the formula 'desired dose/the dose on hand x the quantity'. I know others have mentioned it in previous posts but honestly I can say that if it were not for this formula (and others like it for IV calculations) I would not have passed dosage calc let, alone get a 4.0 in it. The one thing that I do know about math is that there are always multiple ways to solve the problems you just need to explore them and find the way that makes sense to you. Like anything you have to practice to become proficient (sp) but after a little while it should start making sense and you should start noticing that the info you need to solve the problem starts jumping out at you. I hope this helps. Check into the desired dose/dose on hand x qty formula....it has been a life saver for me. Good luck to you.

Music in My Heart · Jul 13, 2009

Drug calculations are all word problems; with word problems a picture is always worth a thousand words. The reason most people have trouble with these are because they don't make sense until they get into clinical situations and actually see and hold in their hands the actual things these drug problems are talking about and suddenly light bulbs turn on all over your brains.

I agree that many people have trouble in going between the tangible and the intangible.

In my tutoring I've used a digital food scale, M&Ms, a bottle of water, and a medicine dropper to help try to get my students to THINK about what they're doing and not simply try to "plug-and-play" with the formulae. It seems to be quite helpful in getting those light bulbs turned on.

Dianacabana · Jul 13, 2009

I highly recommend you find a copy of Math for Meds by Anna Curren. I'll bet its at your library. It shows you how to do these exact types of calculations, step by step. Lots of practice problems, too.

I know the stress of the grades you need must be awful. Take a deep breath, make a plan of what math topic(s) you plan to study each day and begin there. You are certainly smart to be looking for help.

Does your instructor have any recommendations for study tools? I have found that most teachers will bend over backward to help those looking to help themselves. Just ask. If it doesn't turn out the way you hope, find another way to make it work.

BEST of luck to you!

LaneRN · Jul 15, 2009

If you sre still having problems pm me and I will send you the notes that were gave to us in class on how to do this so far I have passed all of mine. I am in the nursing program and we had to have a 90% are we failed out no matter what your other grades are. So if you need it just let me know.

CrunchyMama, ASN, RN · Jul 18, 2009

I don't know if this has been mentioned but I bought the book "Dosage Calculations Made Incredibly Easy" and it has helped me so much. Well I don't start nursing until next month but I HATE math and it explains conversions and formulas very well. So I'd suggest this book.....good luck!

kgorndt · Jul 18, 2009

hi crunchymama! Is there anyway I could get the author name from you? Did you get that from a bookstore like Barnes & Noble or from your college?